The inventive concept relates to a semiconductor memory device. More particularly, the inventive concept relates to a semiconductor memory device having a three-dimensional (3D) cross-point array that includes vertically stacked variable resistance memory cells.
A resistance random access memory (RRAM) is a memory device using a resistance varying property of a transition metal oxide, that is, a property in which the resistance of the material differs according to a state of the material. In the case of an RRAM, research has been actively conducted into a 3D cross-point array structure to meet the demand for a highly integrated memory device. The 3D cross-point array structure is a structure in which a plurality of upper electrodes and a plurality of lower electrodes are formed to cross each other and memory cells are disposed at cross points. The 3D cross-point array structure is advantageous in storing and reading data because random access is possible; however, a current path is formed between a memory cell that has been accessed and adjacent memory cells, and thus, a large leakage current may occur. Thus, electric characteristics may be degraded and it may be difficult to form a highly integrated memory device.